Aqua Select® OTO ½ oz Refill

This ½ oz bottle of OTO (Orthotolidine) checks your pool water's chlorine level. OTO is a reliable test solution that accurately measures the free chlorine present in your pool. With just a few drops, the solution will change color, indicating whether your chlorine levels are too high, too low, or within the optimal range.

Note: Read back panel carefully, be sure to keep OTO solution away from skin and eyes. Keep this tester out of reach of children.